Electrolytic process and product.



M. ERRITT.

ELECTHOLYTI R0 AND PRODUCT.

APPLICAT N E 0.8.1917.

Lwo Patented 001:. 22, 1918.

aan amc.

MATTHEW MERRITT, OF SOUTH MIDDLETON, MASSACHUSETTS, ASSIGNOR TO COPPER PRODUCTS COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

ELECTROLYTIC PROCESS AND PRODUCT.

Specification of Letters Patent.

Patented Oct.. 22, 1918.

Original application led November 2, 1917, Serial No. 199,809. Divided and this application iiled December 8, 1917. Serial No. 206,294.

To all 'whom t may concern:

Be it known that I, MATTHEW M. MER- Rrr'r, a citizen of the United States, and a resident of South Middleton, county of Essex, Commonwealth of Massachusetts, have invented an Improvement in Electrolytic Processes and Products (B), of which the following description, in connection with the accompanying drawings, is a specification,- likeI characters on the drawings representing like parts.

This invention pertains to improvements in electrolytic processes and products, and more particularly, though not exclusively, to improvements in the manufacture of articles, such as aeroplane propellers formed of non-conductive materials and coated with electrolytically deposited metal.

This application is a division of my copending application, Serial No. 199,809, filed November 2, 1917.

In the drawings that show one form of an illustrative embodiment of my invention:

Figure shows an aeroplane propeller coated with copper;

Fig. 2 is a diagrammatic section therethrough on the line 2 2 of Fig. l.

lI have found in electrolytically depositing metal on the surface of non-conductive bodies that the usual method of applying a paint of granular electrically conductive particles and a binder to the surface of the article to be coated, and subsequently electrolytically depositing metal such as copper on the surface of the electrically conductive coating, the deposited metal, partaking of the structure of the electrically conductive coating, is coarsely crystalline, very brittle, and of apparently slight tensile strength. I have found that the texture of the deposited copper may be greatly improved, its brittleness decreased and its tensile strength increased, by interposing between the initial electrically conductive coating and the copper deposit a lm or stratum of foreign substance such as grease. I believe that this improved result is due to the equalization of attraction of the entire surface of the cathode. Where the -deposit is made directly on the the coatlng exerts a considerably" greater attraction for the ions in the bath than is exanular coating, each particle of erted by the interstices between the grains, thereby separating the copper deposit in coarsely crystalline formation. When, on the other hand, a film of grease is interposed between the entire surface of the granular electrically conductive coating and the electrolyte, the attraction exerted by an exterior projecting point of each individual grain of, the initial coating is considerably I believe this to be of advantage'in articles which are flexible," notably aeroplane propellers. It is also of advantage because any tendency of the metal to become crystalline as deposit continues becomes checked. Thus if, for any reason, a portion of the surface of a layer of copper has accumulated occludedr hydrogen and has thereby been rendered more crystalline in structure, a film of the grease will prevent subsequent deposits of metal from partaking of the coarsely rystalline structure of the underlying surace.

I have described in a co-pending application a method of utilizing mercury to secure strong, close-grained metallic deposit on non-conductive cathodes. The present invention may be advantageously combined with the invention disclosed in said co-pending applicationby coating with grease or similar substance the initial application of electrically conductive paint, electrolytically depositing the first layer of metal thereon', coating said layer of metal with the lit will be understood that l have used the Word grease throughout, the specification and claims in a generic sense to include any non-conductive substance capable of forming a film over the conductive surface of a cathode.

While have shown and described one embodiment of my invention and a preferred method of ractising the same, it Will be understood t at great changes may be made therein Without departing from the scope of my invention, which is best deined in the following claims. I'

Claims:

1. The method of coating non-conductive cathodes, which comprises applying there- 'to a coating of electrically conductive granular material, coating said granular material with an exterior iilm of 'a foreign substance, and then electrolytically depositing metal thereon.

2. The method of coating non-conductive cathodes, which comprises applying thereto a coating of electrically conductive granular material, coating said granular material With an` exterior film of grease, and then electrolytically*depositing metal thereon.v

3. rlhe method of coating non-conductive cathodes, which comprises applying electrically conductive surfacing material thereto, subsequently electrolytically depositing a layer of metal thereon, applying an exterior lm of grease to the exterior surface of said electrolytically deposited layer of metal and subsequently continuing electrolytic de osit.

In testimony whereof, l have signe my name to this specification.

' MATTHEW M. MERRITT. 

